Remote Processing CX-10 - Manual (Page 18)

SERIAL PORTS BASIC SECTION 4
Page 4-1
Figure 4-1 Serial Port Locations
DESCRIPTION
SERIAL PORTS SECTION 4
The CX-10 has two serial ports that interface to a
variety of devices. In addition, the port designated as
COM3 can change “personality” This section describes
their characteristics and how to use them.
Battery and switched 5V power are also available at J1
and J2.
Serial ports are numbered COM0 and COM3. COM0 is
RS-232 only and is used for Basic program development.
While running a Basic program, it can be used for other
functions.
COM3 can be configured to operate as a modbus
(default mode) or ASCII port. ASCII port mode is
usable only while running a Basic program.
Additionally, COM 3 has 3 ways to communicate to the
outside word: RS-232, RS-485 (2 wire) and optional 900
Mhz radio.
Under the right conditions, the CX-10 can be networked
with other CX-10 or modbus devices.
The following paragraph may be important to Basic
programmers. Each port has a 256 character interrupt
driven circular input and output buffer. This allows
characters to be sent out (using PRINT) without slowing
down program execution. However, if the PRINT buffer
fills, program execution is suspended until all PRINT
characters are in the buffer. Both ports have a 256
character input buffer. When more than 256 characters
are received, excess ones are ignored.
SWITCHED POWER
Continuous and switched power are available at J2 and
J3. This is generally useful when running a Basic
program and controlling a external display’s backlight or
power. Register 4823 is used to switch +5V power on
and off. Battery power is always available. See “RS-
232 Port Pinout” later in this section for pinouts.